Atmospheric neutrino selection
description
Transcript of Atmospheric neutrino selection
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
• goal: improve efficiencies for both E-2 and atmospheric neutrinos
• strategy– improved hitcleaning– track resolution (paraboloid fit)– zenith restricted fit– Phit/Pnohit fit– no neural networks (or similar)
Atmospheric neutrino selection
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Efficiency of New Analysis
• efficiency > 60% above 120°
atmo. neutrinos 45 % E-2 neutrinos 40 %
relative to L2
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Neutrino Candidates
Ndata NatmoMC
θ>90° 2021 1793
θ>110° 1194 1238
NatmoMC: ± 25%
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Effective Area
• zenith angle dependence
newstd.
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Atmospheric Neutrinos
• neutrino-effective area for energies above 50 GeV
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Corrected Zenith Angle Spectrum
• account for acceptance and oscillations
)GeV(
)km()eV(27.1sin2sin1 222
M2
E
LmP
232 eV104.2 m12sin M
2
SuperKamiokande:
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Restrictions on Δm2?
• neutrino flux relative to flux with 232 eV104.2 m
syst
emat
ic e
rror
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
What do we expect from 6 years?
• 10000 atmospheric neutrinos• study high energy• restrictions on alternative oscillation modells
Energy [TeV] < 0.1 0.1 - 0.3 0.3 - 1 1 - 3 3 - 10 >10
Events 900 2800 3200 1900 900 300
% 9 28 32 19 9 3
90% with energies from 0.1 – 10 TeV
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
MedianRes, Zenith (hard cuts z> 110°)
data 00-03 data 2000 data 2001 data 2002 data 2003
... years behave differently number of dead OM‘s is important!
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Lorentz invariance test
case 2: velocity eigenstates = mass eigenstates
case 1: velocity eigenstates = flavor eigenstates
examine 2 extreme cases:
Glashow - hep-ph/0407087
• neutrino species can have different maximal velocities v1, v2, v3 < c• velocity eigenstates rotated w.r.t. flavor eigenstates by v (and phase )
define Ecritical = Ec=sqrt(m²c / 2v)
E < Ec mass oscillation dominant Ec < E Lorentz violation dominant
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
AMANDA‘s range
survival probability for a for case 2 with Ec = 100 GeV
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Case 1: v = 0
hardly accessible for AMANDA
Ec = 1 GeV Ec = 10 GeV Ec = 100 GeV
Ec = 1 TeV Ec = 10 TeV Ec = 100 TeV
Ec = 1 PeV Ec = 10 PeV Ec = 100 PeV
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Case 2: v = /4
Ec = 1 GeV Ec = 10 GeV Ec = 100 GeV
Ec = 1 TeVEc = 10 TeV
Ec = 100 TeV
Ec = 1 PeV Ec = 10 PeV Ec = 100 PeV
well accessible for AMANDA for Ec< 1TeV
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Ec - cos() - plane
cos()
log
( E
c / G
eV )
exclusion regionscase 2:
(only 2002 data,preliminary)
90 % C.L. Ec ~ 102.5 = 316 GeVv/c ~ 1.2*10-26
99 % C.L. Ec ~ 102.2 = 158 GeVv/c ~ 4.6*10-26
Depends on assumed systematic errors (needs to be studied in detail)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Other studies
There are many (exotic) models around that can be tested:
Quantum decoherence extra dimensions
... and lots of other ideas
extensive ANTARES Monte Carlo study
... see Francis talk
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Additional plots (not shown)
Note: analysis 2000-2003 is very preliminary!
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Standard Analysis
Ndata = 470 NatmoMC= 402 ± 100
atmo. neutrinos 11 % E-2 neutrinos 28 %
• optimized for best sensitivity (E-2 – spectrum)• selected neutrinos 2002
• efficiencies
(for θ>90°)
relative to L2
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Efficiency of New Analysis
• efficiency > 60% above 120°
atmo. neutrinos 45 % E-2 neutrinos 40 %
relative to L2
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Neutrino Candidates
New analysis Standard analysis
12381194θ>110°
17932021θ>90°
NatmoMCNdata
312283θ>110°
437459θ>90°
NatmoMCNdata
NatmoMC: ± 25%
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Effective Area
E-2
• zenith angle dependence
newstd.
• energy dependence
new (for different spectra)
std.
new
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Atmospheric Neutrinos
• neutrino-effective area
• remaining background
contribution to systematic error ~10%
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Data 2000-2003
Level 5 data from Zeuthen 00-03 analysis
Level 6a fits with T.Becka‘s hit cleaning
Hard cuts:Ldiff>30 spaceangle(JAMS,phpnh)<10 spaceangle(pandel,phpnh)<100.4 > Smoothness > -0.4 MedianRes<5 „Soccer cut“
Softer cuts:Ldiff>25 spaceangle(JAMS,phpnh)<30 spaceangle(pandel,phpnh)<10Smoothness > -0.4 MedianRes<5 „Soccer cut“
pandel (seeded 32-Pandel)bayes (seeded 64-Bayes)PhPnh (seeded 10-PhPnh) ParabolaFit on PhPnh
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Data 2000-2003
3543319529182309softer cuts
z>90°
1819169014241075hard cuts z>90°
44,98541,37035,46830,955z>90°, flare<10, Irun
1679157413641075softer cuts z>110°
213204193197lifetime
11761138955746hard cuts z>110°
257,874238,475200,159149,404events L6a
2003200220012000year
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
GPS day vs. Zenith (no cuts)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Zenith vs. Cogz (no cuts)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
Zenith vs. Cogz (hard cuts z> 90°)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
MedianRes vs. Cogz (no cuts)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
MedianRes vs. Cogz (hard cuts z> 90°)
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (no cuts)
data 00-03 data 2000 data 2001 data 2002 data 2003
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (softer cuts z> 90°)
data 00-03 data 2000 data 2001 data 2002 data 2003
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (hard cuts z> 90°)
data 00-03 data 2000 data 2001 data 2002 data 2003
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (hard cuts z> 110°)
data 00-03 data 2000 data 2001 data 2002 data 2003
Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005
MedianRes, Zenith (hard cuts z> 90°)
data 00-03 data 2000 data 2001 data 2002 data 2003